1. Field of the Invention
The present invention relates generally to print element cleaning devices and specifically to a device for cleaning type elements and print heads.
2. Background of the Invention
Print elements require periodic cleaning to insure that the elements consistently produce sharp and clear characters. This is true whether the print element is a "type" element such as those used in typewriters and daisy wheel printers, a "matrix" element such as those used in dot matrix printers, or an "ink jet". element such as those used in ink jet printers.
Traditional type elements can be cleaned manually by soaking the element in a cleaning solution, and then rubbing or scrubbing them with a cloth or a brush. Alternatively, when the type elements are not removed for the cleaning process, they can be cleaned with a cleaning putty, or can be rubbed or scrubbed with a cloth or brush soaked with solvent. While such methods do clean the type elements, all are messy and therefore inconvenient to use. An alternative to these manual methods is shown in U.S. Pat. No. 4,558,482 issued Dec. 17, 1985 to Neuman, et al. which discloses a type element cleaner consisting of a moistened fabric pad supported in a container having a cover configured to engage a type element. When the cover is fastened to the container, the fabric pad and type element are brought into contact. Rotation of the type element against the surface of the moistened fabric pad removes dirt and ink from the type element.
Unlike traditional type element devices, such as those used in typewriters and daisy wheel printers, the so-called dot matrix printers create characters by means of steel pins which are arranged in tight vertical rows on the matrix print head. In response to specific dot matrix commands, various combinations of pin heads are made to project outwardly thereby creating specific characters which are printed on paper as the pin heads strike a typewriter-type ribbon. The ink jet printers use neither pins nor ribbons since they create characters by squirting small jets of ink onto the paper.
Not all of the ink in an ink jet printer ends up in the paper; some ends up on the print head and eventually must be cleaned off. The same is true of the dot matrix print head. In that case, the pin heads get dirty from the ink on the typewriter ribbon and so they too must periodically be cleaned. Unfortunately many prior art cleaning methods require removal of the ink jet or dot matrix print head prior to cleaning. Despite the claims of modern manufacturers that print heads can be assembled easily and rapidly, the print head removal requirement usually means that a technically trained professional will have to be involved in the cleaning process. The need for professional help when cleaning the print head is not only costly but may also mean the print heads are not cleaned as often as they should be.
A number of different systems have been developed to clean ink jet and matrix print heads. For example, U.S. Pat. No. 4,479,136 issued Oct. 23, 1984 to Lewis, et al. discloses a cleaning system for use on ink jet printers. The Lewis system consists of a cleaning card and a card guide device. When the person using the cleaning system inserts the cleaning card between the card guide and the print head, the card guide device positions the front face of the cleaning eard, so that as the card is pushed down by the user it comes in contact with the ink jet print head. The Lewis cleaning card has a foam strip secured along the bottom of its front face. Prior to use the foam strip is saturated with cleaning solvent. When the cleaning card is inserted between the card guide and the print head, the foam strip is squeezed, thereby releasing the solvent to clean the print head. Movement of the cleaning card wipes the face of the print head with the sponge, thereby cleaning it.
German Patent Application No. DE 34 42 677 Al, filed Nov. 23, 1984 by Winfried Labuda, discloses a cleaning paper for matrix print heads. The Labuda paper is the width of standard continuous feed printer paper, and like continuous feed paper, has marginal perforations which are engaged by the printer's paper feed gear mechanism. Unlike conventional printer paper, the Labuda cleaning paper is composed of a hard, flexible, alcohol resistant layer and a soft, absorbent cleaning material layer. The hard, alcohol resistant layer has a recess in it which resembles a window; the soft, absorbent cleaning material covers the window. According to the teaching of the Labuda application, using only the paper drive mechanism of the printer whose print head is to be cleaned, the cleaning paper can be positioned so that, once the ribbon is removed, the print head can "print" onto the cleaning paper. Part of the cleaning paper will have been saturated with a cleaning solvent so that, as the various characters are created, sometimes the pin heads will come in contact with solvent soaked paper. At other times the pin heads will touch dry paper which will tend to absorb the ink and grime dissolved by the solvent, thus cleaning the print head.
Devices such as those disclosed by Neuman, Lewis and Labuda are useful when there is time for the printer to "go down" to be cleaned and there is money to purchase the mechanical cleaning devices. Sometimes however, it is not possible or convenient to "shut down the presses" and give the type elements or print heads a good cleaning. Such is the case if the print quality begins to deteriorate in the midst of a big printing task, or in the midst of printing a specific document. At times like this a user does not want to stop and turn off the printer, thus losing the printing parameters. The user also does not want to remove the paper and the ribbon cartridge and bypass the "cartridge-in-place" sensor switch before being able to clean the print head. Instead the user wants to momentarily halt the printing or typing process and then quickly and easily clean the type element or the print head. Thus there is a need for a simple cleaning device that can be used by untrained personnel even in the midst of a big typing or printing task. Such a device should be simple to use, inexpensive to purchase, and not require that the typewriter or printer be shut down or dismantled in order to clean the type element or print head.